Hydraulic cushion for sheet-metal presses



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5 Sheets-Sheet 1 F. J. RODE HYDRAULIC CUSHION FOR SHEET METAL PRESSES Filed May 11, 1928 ,1930. F. J. RODE 1,777,130

HYDRAULI C CUSHION FOR SHEET METAL PRESSES Filed May 11, 1928 3 Sheets-Sheet 2 pi. 30, 1930. I F. J. RODE v 11777,113@

HYDRAULIC CUSHION FOR SHEET METAL PRESSES Filed May 11, 1928 s sheets-sheet s V @atented Sept. 30,. 1930 nniran srA'rEls PATENT OFFICE v raanai'cn a nonn, or oHrcAeo, rumors, nssrenoa'ro MARQUET'IE room a mac. 00.,

' or CHICAGO, rumors, a conrona'rron or ILLINOIS mnnnunrccusirron non SHEET-METAL rnnssns Applicationfiled May 11,

This invention relates to improvements in hydraulic cushions particularly adapted, though not necessarily limited in its use in sheet metal presses in which the metal is shaped by means of co-operating dies, one of which is reciprocable toward and away from the other, the work being clamped or held by means of a blank or work holding element that co-operates with the reciprocating die member, the blank or work holder being resisted in its movement in one direction by the said cushion.

Heretofore in cushions of this type the liquid constituting the hydraulic resistance creating medium has been supplied to the cushion from a suitable source, such as a tank, and the liquid in the tank has been subjected to the necessary air pressure for that purpose, and has been supplied from a remote source.

It is one of the objects of the present invention to rovide improved means, preferably in the orm of a-pump device, for circulating the liquid from the tank or source of supply to the cushion to build up the necessary or required pressure and for also returning the blank nr work holder to its'norma-l position, the being continuously operated, avportion of the liquid circulated thereby being trapped to create the predetermined or* necessary resistance pressure, while another portion of the liquid is circulated back to the tank or supply.

A further object of the invention-is to provide an improved hydraulic (cushioning device of this character in which the circulation of a portion of the liquid will be interrupted while the circulation of another portion of the liquid will remain constant, there- :difi'erent kinds of pressure to return the presprovide in an hydraulic cushion of this character improved means whereby the degree of resistance pressure of the liquid to the blank or work holding means may be varied at will at any time 1928. Sei'ial No. 276,868.

in the cycle of; operation of the press to which the cushion is applied. To the attainment of these ends and the accomplishment of other new and useful objects as will appear, the invention consists in the features of novelty in substantiallythe construction, combination and arrangement ofthe several parts hereinafter mo e fully.

described and claimed and shown in he accompanying drawings illustrating this invention, and in which Figure 1 is a view partly in elevation, p'artly in section, and with parts omitted, of an nydraulic cushion device of this character constructed in accordance with the principles of this invention applied to the press and showing the parts in one position, that is in the position in which the blank or work holding element will be resisted byqthe liquid pressure.

Figure 2 is a View similar to Figure 1 with parts omitted and on an enlarged scale, showing some ofthe parts in another position from that shown in Figure 1. a

Figure 3 is a top .plan view of Figure 1, with arts omitted; Reterring more particularly to the drawings-the numeral 10 designates the bed of a press having uprights 11 between whicha reciprocating ram 12 operates and which ram carries a movable die member 13. p

Mounted upon the bed of the press in any suitable manner is adie 14 with which the die 13 co-operates. Ablank or work hold; ing member 15 encompasses the die 14 and co-operates with the die 13 to clamp the work 16 therebetween, and which work is formed over the die 14. x

The blank or work holding-element 15 is ass through the bed plate and are supported y means of a pad or cushioning element 18.

All of the above referred toparts are of of the press, although the cylinder and piston elements may be Separate from the bed the ordinarycand' well known construction. 1

' rection, but will close to prevent the back ward movement by means of liquid 20 supplied to the cylinder through an opening 21 and a pipe 22 which receives its supply from a suitable source, such as a tank 23.

Leading from the tank 23 is a pipe 24 which has communication with the inlet side of the type.

Leading from the outlet of the pump casing is another pipe 26 which has communication with a coupling or joint 27 and the coucasing of a pump 25, preferably of the rotary pling or joint 27 has communication with a valve casing 28, and with which valve casing 28 the pipe 22 also has communication so that when the pump is operated liquid will be drawn from the tank 23 through the ipe 24, pump casing 25., pipe section26, coup ing 27, valve casing 28 and pipe 22, and delivered into the cylinder 19. 7

Within the' valve" casing 28 is a valve 29 preferably of the flap type which co-operates with a seat 30 and is adapted to open, as shown in Figure 1, to ermit the liquidto flow therethrough into t e pipe 22 in one dipressure of the liquid from flowing through the casing 28 back into the pipe 26. 4

Communicating with the coupling 27 and leading therefrom is a pipe 31 which also hascommunication with a valve casing 32 in which a valve 33 operates. The valve 33 is controlled by means of a spring 34 set to a predetermined pressure and leading from the valve casing 33 is a pipe 35 which also has 7 communication with the tank or receiver 23 to deliver the liquid back into the tank.

The pump-25 is operated in any suitable manner preferably by means of a motor 36 to the shaft 37 of which the rotor of the pump a is connected. The pump is continuously operating and the operation of the mechanism thus far described will be as follows:

Liquid will be drawn from the tank 23 and forcedpast the valve 29, through the pipe 22 into the cylinder 19, to raise the piston or pad 18 to the position shown in -Figure 1, and

thereby hold the blank or work holding ele- 3qen1t415 substantially flush with the top of the The upward movement of the pad or piston 18 is arrested by its engagement with the bottom of the bed plate of the press. As the pump is continuously operating and as the piston orpad 18 is arrested in its upward movement, it will be manifest that unless provision is made to take care of the excess pressure created by the pump and to permit raised, the liquid circulated by the pump 25 will escape through the pipe 31 and will unseat the valve 33 against the stress of the spring 34 to flow through the pipe 35 back into the tank 23. I it will be manifest that with the parts in the position shown in Figure 1, there will be a continuous circulation of a portion of the liquid from the tank 23 back to the tank again while the circulation of the portion of the liquid in advance of the valve 29 will be arrested so that when the pad or piston 18 is lowered during the forming of the work, and against the trapped portion of the liquid, a predetermined resistance pressure will he created against such movement of the pa or piston. I

This resistance pressure is controlled by means of a valve 38 which controls a bypass opening 39 leading from the valve casing 28 on the normal outlet side of the valve 29 in the casing 28. The by-pass 39 embodies a pipe 40 which leads around the valve '33 and has communication with a coupling 41 which in turn has communication with the pipe 35 that leads to the tank.

The valve 38 may be held seated under a predetermined pressure in any suitable manner preferably by fluid pressure, and to that end there may be provided a cylinder 42 to which the valve stem 43 of the valve 38 is connected. 7 1

The cylinder 42 is supported in any suitable manner preferably by supporting means 44,and within this cylinder is a piston 45 that remains stationary. A pipe 46 leading from any suitable source of fluid pressure supply is connected with the piston 45 and opens therethrough to the lower side of the plston so that when air pressure is admitted through the pipe 46 to the underside of the piston 45 it will-move the cylinder 42 downwardly whiie the piston remains stationary and will thus close the valve 38, holding the valve against its seat under the predetermined pressure exerted between thelower face of the piston 45 andthe bottom of the cylinder 42. a

This pressure upon the valve v"38 is sufficient to maintain the predetermined pressure against the movement of which the pad or plston 18 operates. When, however, the resistance pressure upon the valve 38 is overcome by the pressure of the pad or piston 18 upon the trapped liquid 20, the valve 38' will be unseated and the trapped liquid will then escape through the by-pass opening 39, pipe .40, coupling 41, around the valve 33 and through the pipe 35 back into the tank 23.

The resistance pressure of the valve 38 may be varied as desired to vary the resistance pressure of the liquid 20.

As soon as the pressure of the liquid under the action of the lowering movement of the pad or piston 18 against the valve 38 is over come by the pressure in the cylinder 42, the valve 38 willtbe closed.

' As soon as the pressure of the liquid under the lowering movement of the pad or piston '18 upon the valve 29' is overcome, the pump or liquid circulating device 25. will force the liquid which it withdraws from the tank 23 past the valve 29 and into the cylinder 19 to raise the pad or piston 18 and thereby restore the blank or work holding element 15 to its normal position. 1

By providing pipes" 47 which lead from a coupling between the coupling'27 and the valve 28 and by providing additional pipes 48 which lead from the coupling 41, as shown in Figure 3, it will be manifest that a series of cushioning devices may be coupled together, thereby extending the scope and capacity of the mechanism.

, If desired and in order not to interfere with the lowering movement of the pad or piston 18 a suitable vent opening 49 may be provided for theescape of any air which may find its way into the cylinder 19 on the top side of the pad or piston 18.

While the preferred form of the invention hasbeen herein shown and described, it is to be understood that various changes may be 7 made in the details of construction and in the combination and arrangement of the several parts, within the scope of the claims, without departing from the spirit of this invention. I

What is claimed as new is 1. A pressure cushion for sheet metal presses-embodying cylinder and piston members, hydraulic means for resisting the relative movement ofsaid members in one direction, a container forholding a supply of liquid, a conduit for delivering the liquid from the container to said cushion, means v for inducing a circulation of the liquid from the. container to the cushion, and means for trapping and maintaining a portion of the liquid against circulation while a continuous c1 culation of another portion of the liquid will he'maintained from the containerand hack thereto.

2. A pressure cushion for sheet metal presses embodying cylinder and piston members, hydraulic means for resisting the relative movement of said members in one direction, a container for holding a supply of liquid, a conduit fbr delivering the liquid fromthe container to said cushion, means for inducing a circulation of the liquid from the container to the cushion, means for trapping and maintaining a portion of the liquid against circulation while a continuous circulation of anot'er portion of the liquid will he maintained from the container and back thereto, means for permitting the escape of said trapped liquid, and variably yielding means for controlling the last recited means.

3. -A' pressure cushion for sheet metal resses embodying cylinder and piston memers, hydraulic meansdfor resisting the relative movement of said members in one direction, a container for holding a supply of liquid, a conduit for delivering the liquid from said container 'to the cushion, means for in ducing circulation of the liquid through the conduit, means embodying a valve for trapping and maintaining a portion of the liquid against circulation while another portion of the liquid may be circulated from the container and back thereto, and means permit said container to the cushion, a continuously operating pump device for circulatin the liquid throu h the conduit, means em odying a valve or trapping and maintaining a against circulation while portion of the liqui another portion of the liquid maybe circu lated from the container and back thereto,

means permitting the trapped liquid to escapeand to be circulated back to the contamer when a predetermined pressure has been obtained upon the trapped liquid, the last recited means embodym a by-pass around said valve, and varia lyyielding means controlling the said h -pass.

5. A pressure cushion or sheetmetal pressesembodying cylinder and piston members, hydraulic means for resisting the relative movement of saidmembers .in one direction, a conduityfor delivering liquid to the cushion, continuously operating means for circulating the liquid through the con--- duit, means for interrupting the circulation of a portion of saidliquid while the circulaton of another portion of the liquid remains constant, and means yieldableto-a predetermined pressure created upon the uiescent liquid by the relative. movement 0 said members in the opposite direction whereby the last said liquidwill escape .to he, a ain circulated with the said other portion 0 the liquid.

6. A pressure cushion for sheet metal resses embodying cylinder and piston memrs, hydraulic means for resisting the relative movement of sad members in one direction, a conduit for delivering liquid to the cushion, continuously operating meansv for circulating thefliquid through the conduit,

means for interrupting the circulation of a portion ofsaid liquid. while the circulation of another porton of the liquid remains constant, means *yieldable to a predetermined ressure created upon the uiescent li uid y the relative vmovement said mem rs in the opposite direction whereby the last said liqu1 will escape to be again circulated with the said other portion of the liquid, and means for varying at will the pressure necessary to overcome the last recited means.

7 A pressure cushion for sheet metal resses embodying cylinder and iston memrs, hydraulic means for resisting the relatlve movement of said members in one dlrection, a conduit for supplying liquid'to the cushion, mechanical means for inducing circulation through the conduit, a valve in the conduit for trapping a portion of the liquid to establish a predetermined resistance pres-.-

sure to the-relative movement of said members in the opposite direction, a branch lead-- ti ve movement of said members'in one direction, a conduit for supplying liquid to the I cushion, mechanical means for inducing circulation through the conduit, a valve in the conduit for trapping a portion of the liquid to establish a predetermined resistance pressure to the relative movement of said members in the opposite direction, a branch leading from said conduit on one side of the valve,

vescape passage for the trapped liquid, and

presses embodying a work holding element,

a plunger for resisting the movement of'said element in one direction, a predetermined supply of liquid operating upon said plunger, mechanical means for maintaining a portion of the liquid in circulation, means for trapping a portion "of the liquid, and means for controlling at will the degree of pressure of the said trapped liquidagainst whichthe said plunger 1s operable by the pressure of the said .work holding element.

11. A pressure cushion for sheet metal presses embodying a work holding element, a plunger for resisting the movement of said element in one direction, a predetermined supply of liquid operating upon said plunger, constantly operating mechanical means for maintaining a portion ofthe'liquid in circulation, means for trapping a portion of the liquid, and means for controlling at will the degree of pressure of, the 7 said trapped liquidagainst which thesaid plunger is operable by the pressure of the said work holding element.

.12. A pressure cushion for sheet metal presses embodying a work holding element, a plunger for resisting the movement of said element in one direction, a predetermined I supply of liquid operating upon said plunger, mechanical means for maintaining a portion of theliquid in circulation, means for trapping a portion of the liquid, an

means for controlling the said escape passage whereby the degree of resistance presa by-pass leading around said valve from the other side thereof and communicating with 'said branch, means for controlling the byass, and fluid ressure means for control 7 lingthe last said means.

cating with said branch, means for control-' 9, A pressure cushion for sheet metal resses embodying cylinder and piston memrs, hydraulic means for resisting the relative movement of said members'in one direction, a conduit for supplying liquid to the cushion, mechanical means for inducing circulation through the conduit, a valve in the conduit for trapping a portion of the liquid to establish a predetermined resistance pressure to the relative movement of said members in the opposite direction, a branch lead ing from said conduit onone side of the valve, a by-pass leading around said valve from the other side thereof and communiling the by-pass, and variably yielding means or controlling the last said means, the said liquid circulating means being also operable to cause the liquid to impart a relative movement to the cylinder and piston members in one direction.

1 0. A pressure cushion for sheet metal sure of the trapped liquid against the plunger is operab e by the pressure of the work holding element may be varied.

13. A pressure cushion for sheet ,metal presses embodyinga work holding element, a plunger for resisting the movement of said element in one d1rection,'a container for containing a predetermined supply of liquid, a conduit for delivering the liquid from the container to operate upon the plunger, means connected with the conduit for circulatin the liquid therein, a valve in the conduit liquid to establish a resistance pressure against which the plunger is operable, a bypass leading around said valve to permit the trapped li uid to escape, means for controlling said y-pass to establish a predetermined resistance pressure of the liquid against which the piston operates, a branch plpe also leading container whereby a portion of the liquid will be maintained in circulation, and meansrom said conduit to the' ibr trapping a portion of the taining a predetermined supplyof liquid, a

conduit for delivering the liquid from the container to operate upon the plunger, means connected with the conduit for circulating the liquid therein, a valve in the conduit for trapping a portion of the liquid to establish a resistance pressure agalnst which the plunger is' operable, a by-pass leading around said valve to permit the trapped li uid to escape, means for controlling said y-pass to establish a predetermined resistance pressure of the liquid against which the piston operates, a branch pipe also leading from said conduit to the container whereby a portion of the liquid will be maintained in circulation, and means for controlling said branch pipe, the said liquid circulating means also operating to cause the liquid to directly act upon said plunger for returning the Work holder to normal position.

In testimony whereof I have signed my name to this specification, on this 8th day of May, A. D. 1928.

FRIEDRICH J RODE. 

